With developments in digital signal processing technology, digital cameras have come to the forefront and have replaced analog cameras. Digital cameras generally require a mechanism for driving a lens so as to adjust the focus of the lens when taking pictures. In general, lens driving mechanisms are often achieved by motors, plungers, or the like. However, since efforts for size reduction of electromagnetic components such as motors and plungers have been successful only to a limited degree, it is difficult to build electromagnetic components, such as the ones described above, into compact digital cameras such as mobile phones. In the related art, there are documents that disclose lens driving technology in which shape-memory alloys are used as a driving source without using electromagnetic components (e.g., see patent document 1).    [Patent document 1] WO 07/113478 pamphlet